Discharge tube, ferrule, lighting device, display device and television receiver

ABSTRACT

In a discharge tube, a conductive ferrule is provided on an end portion of a glass tube. The ferrule includes a body that is to be mounted to the outer circumference of the glass tube and has a contact portion to be electrically conductively fixed to a relay connector (or a bearing device). Further included is a conductive portion that extends from the body so as to have elastic contact with an outer lead. The outer lead will not be under load due to the weight of the discharge tube, but the conductive portion solely has elastic contact therewith. Thus, stress concentration on the outer lead can be prevented.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a discharge tube, a ferrule, a lightingdevice, a display device and a television receiver.

2. Description of the Related Art

An example of a lighting device capable of functioning as a backlightfor a liquid crystal display device is disclosed in JP-A-2004-294592.The lighting device has a structure in which the end portions of aplurality of elongated discharge tubes are fixed to respectiveconnecting members mounted to a substantially flat plate-shaped chassis,and power boards are also fixed to the respective connecting members. Anouter lead projecting from the end portion of the discharge tube isconnected to the power board via the connecting member.

In the discharge tube, the outer lead penetrates the end portion of theglass tube. The connecting member is fitted solely onto the outer lead,so as not to have contact with the glass tube. Therefore, stress isconcentrated on the outer lead. The concentration of stress may yield atiny gap formed between the glass tube and the penetrating outer lead.This will cause a phenomenon to slowly leak air from the glass tube,which is called a slow leak.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention were made in view of theforegoing circumstances, and prevent stress concentration on an outerlead.

A discharge tube according to a preferred embodiment of the presentinvention includes a glass tube, an outer lead arranged to project froman end portion of the glass tube and to be capable of receiving powersupply from a power source, and a ferrule having a body and a conductiveportion. The body is mounted to the outer circumference of the glasstube, and has a contact portion arranged to be electrically connected tothe power source. The body is arranged to be supported by a bearingdevice. The conductive portion extends from the body, and is connectedto the outer lead.

According to a preferred embodiment of the present invention, the bodyof the ferrule can be borne by the bearing device in order to supportthe discharge tube, and therefore the outer lead will not be under loaddue to the weight of the discharge tube. Thus, stress concentration onthe outer lead can be prevented.

In the discharge tube according to a preferred embodiment of the presentinvention described above, a valley may be formed on the distal end edgeof the conductive portion, so that the outer lead can be connected tothe conductive portion while being fitted into the valley.

In this case, the conductive portion can be infallibly connected to theouter lead, because the outer lead is arranged to be fitted into thevalley provided on the distal end of the conductive portion.

In the discharge tube according to a preferred embodiment of the presentinvention described above, the conductive portion can include a longportion continuous with the body, and a wide portion continuous with thedistal end of the long portion, so that the wide portion has contactwith the outer lead.

In this case, a large area of the wide portion along its width directioncan be secured to have contact with the outer lead, resulting ininfallible contact therebetween. On the other hand, the long portionthat is immune to contact with the outer lead is preferably small inwidth and thereby is prone to elastic deflection. Consequently, contactpressure applied to the outer lead can be reduced.

In the discharge tube according to a preferred embodiment of the presentinvention described above, a protector portion may be provided on thebody so as to be located on the sides of a proximal portion of theconductive portion.

In this case, deformation of the conductive portion caused byinterference with foreign substances can be prevented due to theprotector portion being provided.

In the discharge tube according to a preferred embodiment of the presentinvention described above, an elastic gripping portion may be providedon the body so as to have elastic contact with the outer circumferenceof the glass tube.

In this case, the elastic gripping portion is arranged so as to haveelastic contact with the outer circumference of the glass tube, andthereby the ferrule can be prevented from rattling or radial movementrelative to the glass tube, even if a large dimensional tolerance is setfor the outer diameter of the glass tube.

In the discharge tube according to a preferred embodiment of the presentinvention described above, the glass tube can have a substantiallycylindrical shape and the body can have a cylindrical shape that issubstantially concentric with the glass tube, in which the contactportion may be formed along the circumferential direction of the body.

In this case, the contact portion is provided along the circumferentialdirection of the cylindrical body, and therefore connection to a relayconnector can be achieved without considering the angle of the dischargetube about its axis.

In the discharge tube according to a preferred embodiment of the presentinvention described above, the glass tube can have a substantiallycylindrical shape and the body can have a cylindrical shapesubstantially concentric with the glass tube, in which the contactportion may be formed of a rib-shaped protrusion provided continuouslyalong the circumferential direction of the body, and a larger diameterportion having an outer diameter larger than that of the contact portionmay be provided on the body.

When the discharge tube is put on a workbench or the like, the surfaceof the contact portion formed as a rib-shaped protrusion may getscratched due to contact with the workbench. However, according to thepresent construction, the large diameter portion, which is formed tohave an outer diameter larger than that of the contact portion, canprevent the contact portion from being scratched.

In the discharge tube according to a preferred embodiment of the presentinvention described above, the glass tube can have a substantiallycylindrical shape and the body can have a cylindrical shapesubstantially concentric with the glass tube, in which a plurality ofelastic gripping portions capable of contact with the outercircumference of the glass tube may be provided on the body so as to becircumferentially spaced apart. A gap is formed between the outercircumference of the glass tube and the inner circumference of the bodyso as to extend over the substantially entire circumference.

In this case, the gap, i.e., airspace having a thermal conductivitylower than that of metal or synthetic resin, is provided between theouter circumference of the glass tube and the inner circumference of thebody so as to extend over the substantially entire circumference.Thereby, heat transfer from the glass tube to the body side can beprevented and minimized, and consequently reduction in internaltemperature of the glass tube can be prevented. The suppression oftemperature reduction in the glass tube can prevent cohesion of mercurycapable of being encapsulated in the glass tube. This enables retentionof luminescent performance.

In the discharge tube according to a preferred embodiment of the presentinvention described above, the glass tube can have a substantiallycylindrical shape and the body can have a cylindrical shapesubstantially concentric with the glass tube, in which a plurality ofelastic gripping portions capable of contact with the outercircumference of the glass tube may be provided on the body so as to becircumferentially spaced apart. A gap is formed between the outercircumference of the glass tube and the inner circumference of the bodyso as to extend over the substantially entire circumference. Theplurality of elastic gripping portions may be arranged to have contactwith the outer circumference of the glass tube at a plurality ofpositions spaced along the axial direction of the body.

In this case, the elastic gripping portions have contact with the glasstube at the plurality of axially-spaced positions. Thereby, the body ofthe ferrule is secure from changing its orientation and consequentlyforming an angle with the axis of the glass tube.

In the discharge tube according to a preferred embodiment of the presentinvention described above, a cylindrical portion, which iscircumferentially connected to the outer lead so as to surround it, maybe provided on the conductive portion.

In this case, the conductive portion includes the cylindrical portioncapable of circumferentially surrounding the outer lead, and thereby theconductive portion is prevented from disengaging from the outer lead.Consequently, the conductive portion can be infallibly connected to theouter lead.

As a means for achieving the above advantages, a ferrule according to apreferred embodiment of the present invention, which has conductivityand is to be mounted to a discharge tube that includes a glass tubehaving an outer lead projecting from an end portion thereof so as to becapable of receiving power supply from a power source on the outer lead,includes a body that is to be mounted to an end portion of the outercircumference of the glass tube and to be borne by a bearing device andhas a contact portion to be electrically connected to the power source.Further included is a conductive portion that extends from the body andis to be connected to the outer lead.

According to a preferred embodiment of the present invention, the bodyof the ferrule can be borne by the bearing device in order to supportthe discharge tube, and therefore the outer lead will not be under loaddue to the weight of the discharge tube. Thus, stress concentration onthe outer lead can be prevented.

In a ferrule according to a preferred embodiment of the presentinvention described above, a valley may be formed on the distal end edgeof the conductive portion so that the valley of the conductive portioncan be connected to the outer periphery of the outer lead.

In this case, the conductive portion can be infallibly connected to theouter lead, because the valley capable of being fitted onto the outerperiphery of the outer lead is provided on the distal end of theconductive portion.

In a ferrule according to a preferred embodiment of the presentinvention described above, the conductive portion can include a longportion continuous with the body, and a wide portion continuous with thedistal end of the long portion, so that the wide portion can havecontact with the outer lead.

In this case, a large area of the wide portion along its width directioncan be secured to have contact with the outer lead, resulting ininfallible contact therebetween. On the other hand, the long portionimmune to contact with the outer lead is formed so as to be small inwidth and thereby be prone to elastic deflection. Consequently, contactpressure to be applied to the outer lead can be reduced.

In a ferrule according to a preferred embodiment of the presentinvention described above, a protector portion may be formed on the bodyso as to be located on the sides of a proximal portion of the conductiveportion.

In this case, deformation of the conductive portion caused byinterference with foreign substances can be prevented due to theprotector portion being formed.

In a ferrule according to a preferred embodiment of the presentinvention described above, an elastic gripping portion capable ofelastic contact with the outer circumference of the glass tube may belocated on the body.

In this case, the elastic gripping portion can have elastic contact withthe outer circumference of the glass tube, and thereby the ferrule canbe prevented from rattling or radial movement relative to the glasstube, even if a large dimensional tolerance is set for the outerdiameter of the glass tube.

In a ferrule according to a preferred embodiment of the presentinvention described above, the body can have a cylindrical shape capableof being substantially concentric with the glass tube that has asubstantially cylindrical shape, in which the contact portion may beformed along the circumferential direction.

In this case, the contact portion is provided along the circumferentialdirection of the cylindrical body, and therefore connection to a relayconnector can be achieved without considering the angle of the dischargetube about its axis.

In a ferrule according to a preferred embodiment of the presentinvention described above, the contact portion can be formed of arib-shaped protrusion provided continuously along the circumferentialdirection, and a large diameter portion having an outer diameter largerthan that of the contact portion may be formed on the body.

When the discharge tube is put on a workbench or the like, the surfaceof the contact portion formed as a rib-shaped protrusion may getscratched due to contact with the workbench. However, according to thepresent construction, the large diameter portion, which is formed tohave an outer diameter larger than that of the contact portion, canprevent the contact portion from being scratched.

In a ferrule according to a preferred embodiment of the presentinvention described above, the body can have a cylindrical shape capableof being substantially concentric with the glass tube that has asubstantially cylindrical shape, in which a plurality of elasticgripping portions capable of contact with the outer circumference of theglass tube may be formed on the body so as to be circumferentiallyspaced apart. A gap can be formed between the outer circumference of theglass tube and the inner circumference of the body, in a state of beingmounted to the glass tube, so as to extend over the substantially entirecircumference.

In this case, the gap, i.e., airspace having a thermal conductivitylower than that of metal or synthetic resin, can be provided between theouter circumference of the glass tube and the inner circumference of thebody so as to extend over the substantially entire circumference.Thereby, heat transfer from the glass tube to the body side can beprevented, and consequently reduction in internal temperature of theglass tube can be prevented. The suppression of temperature reduction inthe glass tube can prevent cohesion of mercury capable of beingencapsulated in the glass tube. This enables retention of luminescentperformance.

In a ferrule according to a preferred embodiment of the presentinvention described above, the plurality of elastic gripping portionsmay be arranged to be capable of contact with the outer circumference ofthe glass tube at a plurality of positions spaced along the axialdirection of the body.

In this case, the elastic gripping portions can have contact with theglass tube at the plurality of axially-spaced positions, and thereby thebody of the ferrule is prevented from changing its orientation andconsequently forming an angle with the axis of the glass tube.

In a ferrule according to a preferred embodiment of the presentinvention described above, a cylindrical portion, which is capable ofbeing circumferentially connected to the outer lead so as to surroundit, may be formed on the conductive portion.

In this case, the conductive portion includes the cylindrical portioncapable of circumferentially surrounding the outer lead, and thereby theconductive portion can be prevented from disengaging from the outerlead. Consequently, the conductive portion can be infallibly connectedto the outer lead.

A lighting device according to a preferred embodiment of the presentinvention includes a power source, a discharge tube according to apreferred embodiment of the present invention described above, and achassis provided as a mounting base for the power source and thedischarge tube.

A display device according to a preferred embodiment of the presentinvention includes the lighting device described above, and a displaypanel arranged on the front side of the lighting device.

A television receiver according to a preferred embodiment of the presentinvention includes the display device described above.

These and other features, elements, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of preferred embodiments of the presentinvention with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a discharge tube according to preferredembodiment 1 of the present invention.

FIG. 2 is a partial front view of the discharge tube.

FIG. 3 is a partial plan view of the discharge tube.

FIG. 4 is a side view of the discharge tube.

FIG. 5 is a partial front view of a glass tube.

FIG. 6 is a perspective view of a ferrule.

FIG. 7 is a front view of the ferrule.

FIG. 8 is a rear view of the ferrule.

FIG. 9 is a bottom view of the ferrule.

FIG. 10 is a side view of the ferrule.

FIG. 11 is a horizontal sectional view of a display device.

FIG. 12 is a perspective view of a lighting device.

FIG. 13 is a rear view of the lighting device.

FIG. 14 is a partially-enlarged front view of the lighting device.

FIG. 15 is a sectional view of a relay connector.

FIG. 16 is a perspective view of the relay connector.

FIG. 17 is a sectional view of an on-board connector.

FIG. 18 is an exploded perspective view of a television receiver.

FIG. 19 is a perspective view of a ferrule according to preferredembodiment 2 of the present invention.

FIG. 20 is a side view of the ferrule.

FIG. 21 is a front view of the ferrule.

FIG. 22 is a rear view of the ferrule.

FIG. 23 is a perspective view of the ferrule attached to a glass tube.

FIG. 24 is a front perspective view of a lighting device according topreferred embodiment 3 of the present invention.

FIG. 25 is a front view of the lighting device.

FIG. 26 is a perspective view of relay connectors.

FIG. 27 is a partially-enlarged front view showing a connectingstructure between a relay connector and a discharge tube.

FIG. 28 is a side view of a relay connector.

FIG. 29 is a sectional view showing that a ferrule on a discharge tubeis capable of engaging with a stopper.

FIG. 30 is a sectional view showing a connecting structure between arelay connector and a power board.

FIG. 31 is a perspective view of a discharge tube.

FIG. 32 is a rear view of a ferrule.

FIG. 33 is a plan view of the ferrule.

FIG. 34 is a side view of the ferrule.

FIG. 35 is a rear perspective view of the lighting device.

FIG. 36 is a front view of a lighting device according to preferredembodiment 4 of the present invention.

FIG. 37 is a front view of the lighting device, from which dischargetubes are detached.

FIG. 38 is a rear view of the lighting device.

FIG. 39 is a perspective view of a grounding member.

FIG. 40 is a perspective view of a grounding terminal.

FIG. 41 is a sectional view showing that a ferrule on a discharge tubeis capable of engaging with a stopper.

FIG. 42 is a partially-enlarged front view showing a connectingstructure between a grounding terminal and a discharge tube.

FIG. 43 is a perspective view showing a modification of a ferrule.

FIG. 44 is a side view of FIG. 43.

FIG. 45 is a perspective view of a grounding terminal.

FIG. 46 is a sectional view showing a connection between a groundingterminal shown in FIG. 45 and a ferrule.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred Embodiment 1

A preferred embodiment 1 according to the present invention will behereinafter explained with reference to FIGS. 1 to 18.

Overview of Display Device D

FIG. 18 is an exploded perspective view of a television receiver TV. Adisplay device D included in the television receiver TV is a so-calledliquid crystal display device including a display panel 11 and alighting device 10 as shown in FIG. 11, which preferably has ahorizontally-elongated rectangular shape as a whole. The display panel11 is disposed on the front side of the lighting device 10, so that thelighting device 10 as a backlight can illuminate the display panel 11from the back side. As shown in FIG. 18, the television receiver TVincludes the display device D, and front and back cabinets Ca and Cbcapable of holding the display device D therebetween. Further includedare a power source P other than a power board 16 (corresponding to apower source of the present invention) described below, a tuner T and astand S. FIG. 11 schematically shows the display device D, and thereforethe shapes of relay connectors 14, on-board connectors 18 and the likediffer slightly from those in the other figures.

The display panel 11 has a well-known construction, in which liquidcrystal as a material with an optical property that changes with appliedvoltage is disposed in the gap between a transparent

TFT substrate and a transparent CF substrate. TFTs (Thin FilmTransistors), as switching elements connected to a source wiring lineand a gate wiring line running at right angles to each other, and pixelelectrodes connected to the TFTs are provided on the TFT substrate. Acolor filter, on which color sections of three primary colors, i.e., Red(R), Green (G) and Blue (B), are arranged in a matrix, and a commonelectrode are provided on the CF substrate.

Overview of Lighting Device 10

The lighting device 10 includes a lamp unit 12 and power boards 16. Thelamp unit 12 includes a metallic chassis 13, which preferably has asubstantially horizontally-elongated rectangular plate shape andfunctions as a reflector plate. Further included are a plurality ofdischarge tubes 15 held in a horizontal position and vertically arrangedon the front side of the chassis 13 so as to be parallel orsubstantially parallel to one another, and a plurality of relayconnectors 14 (corresponding to a bearing device of the presentinvention) which are vertically arranged along the lateral edges of thechassis 13 so as to correspond to the discharge tubes 15. The powerboards 16 are disposed on the back side of the chassis 13 so as tosupply power to the discharge tubes 15 via the relay connectors 14.

As shown also in FIGS. 14 and 15, a plurality of mounting holes 13Hcorresponding to the ends of the discharge tubes 15 are formed throughthe chassis 13 so as to extend from the front side to the back side, andare vertically arranged so as to be level with the respective dischargetubes 15. The relay connectors 14 are mounted through the respectivemounting holes 13H. Each relay connector 14 includes a holder 20preferably made of synthetic resin, and a metallic relay terminal 30housed in the holder 20 (See FIG. 16).

As shown in FIGS. 14 to 16, a pair of upper and lower elastic retainingportions 25 and a pair of right and left engaging surfaces 26 are formedon the outer surface of the holder 20. The holder 20 is inserted intothe mounting hole 13H from the front side of the chassis 13, and isfixed to the chassis 13 due to the engaging surfaces 26 in abuttingcontact with the opening edge of the mounting hole 13H on the frontsurface of the chassis 13 and due to the retaining protrusions of theelastic retaining portions 25 being locked by the opening edge of themounting hole 13H on the back surface of the chassis 13. When attachedto the chassis 13, the front end portion of the holder 20 projects tothe front side of the chassis 13, while the back end portion of theholder 20 projects to the back side of the chassis 13. A container room23 is formed in the projecting portion of the holder 20 on the frontside of the chassis 13, by removing the front surface and one lateralsurface thereof. A plate-shaped wall portion 27 is provided on theprojecting portion of the holder 20 on the back side of the chassis 13.The relay terminal 30 is disposed in the holder 20.

The relay terminal 30, which can be formed by bending a metallic platethat is formed into a predetermined shape by punching, includes a tubeconnecting portion 31 having a pair of upper and lower elastic nippingportions 32 formed of plates having a substantially circular arc shape,and further includes a plate-shaped board connecting portion 33projecting to the back side. The tube connecting portion 31 is disposedin the container room 23, while the board connecting portion 33 isarranged along the wall portion 27.

As shown in FIGS. 11 to 13, each power board 16 includes a circuit board17 having a circuit formed on its back surface (i.e., the surface on theopposite side of the chassis 13), electronic components 19 mounted onthe back surface of the circuit board 17, and a plurality of on-boardconnectors 18 mounted on the back surface of the circuit board 17.

The on-board connectors 18 are vertically arranged along the lateralside edge of the circuit board 17 so as to correspond to the respectiverelay connectors 14. As shown in FIG. 17, each on-board connector 18includes a housing 60 made of synthetic resin, and a metallic outputterminal 70 disposed in the housing 60. An engaging recess 63 with avertically-elongated rectangular opening is formed on the front surfaceof the housing 60. The opening of the engaging recess 63 is aligned witha fitting hole 17H that is formed through the circuit board 17 so as toextend from the front side to the back side.

The output terminal 70, which can be formed by bending a metallicmaterial that is formed into a predetermined shape by punching, includesa substantially U-shaped connecting portion 73 capable of elasticdeflection. The connecting portion 73 is partly located in the engagingrecess 63. The end portion of the output terminal 70 on the oppositeside of the connecting portion 73 is connected to the circuit formed onthe circuit board 17.

Discharge Tube 15

As shown in FIGS. 1 to 5, each discharge tube 15 used in the lightingdevice 10 preferably is formed of a cold cathode fluorescent tube thatincludes a generally elongated straight glass tube 40 having a circularcross section, elongated outer leads 42 which have a circular crosssection and project linearly from the respective ends of the glass tube40 and coaxially with the glass tube 40, and further includes ferrules50 attached to the respective end portions 40 a of the glass tube 40.Mercury is encapsulated in the glass tube 40. Each end portion 40 a ofthe glass tube 40 is melted into a substantially hemispherical shape byheat, and thereby forms a domed portion 41. The outer lead 42 penetratesthe domed portion 41.

Referring to FIGS. 6 to 10, each ferrule 50 preferably is a single-piececomponent, which can be formed by bending or hammering a metallic (e.g.,copper alloy) plate that is gilded and formed into a predetermined shapeby punching, for example. The ferrule 50 includes a body 51 and aconductive portion 57. The body 51 generally forms a cylindrical shapeconcentric with the glass tube 40. The inner diameter of the body 51 ispreferably slightly larger than the outer diameter of the glass tube 40.A circumferential rib-shaped contact portion 52 is provided on an outercircumferential surface of the body 51, so as to bulge outward at aposition slightly posterior to the anterior end edge thereof and form acircular shape concentric with the body 51. The contact portion 52 has asubstantially semicircular cross section, so that the outer surface ofthe contact portion 52 can have line contact with the relay connector14. A circumferential rib-shaped large diameter portion 53 is formed onthe outer circumferential surface of the body 51, so as to bulge outwardat a position slightly anterior to the posterior end edge thereof andform a circular shape concentric with the body 51. The large diameterportion 53 has a substantially semicircular cross section. The outerdiameter of the large diameter portion 53 is preferably larger than theouter diameter of the contact portion 52. The contact portion 52 and thelarge diameter portion 53 are arranged respectively on the anterior endside and posterior end side of the body 51, so as to be spaced along theaxial direction of the body 51.

Elastic gripping portions 54 are formed on the body 51 by makingsubstantially U-shaped cuts in tangible portions thereof. Each elasticgripping portion 54 is generally formed as a cantilevered portionextending posteriorly (specifically, in an oblique direction slightlyleaning radially inwardly), which is capable of elastic and radialdeflection with a supported point on its proximal end (or anterior end).A curved portion 54 a is formed on the distal end portion (or posteriorend portion) of the elastic gripping portion 54, so as to curve in anoblique direction leaning radially outwardly. The outer surface of thecurve (or inwardly facing surface) of the curved portion 54 a can abuton the outer circumferential surface of the glass tube 40. Three elasticgripping portions 54 are formed at even intervals along thecircumferential direction. An imaginary line that connects the curvedportions 54 a of the three elastic gripping portions 54 forms a circleconcentric with the body 51. The diameter of the imaginary circle, whenthe elastic gripping portions 54 are not forced into elastic deflectionor are in a free state, is preferably smaller than the outer diameter ofthe glass tube 40. The curved portions 54 a of the elastic grippingportions 54 and the large diameter portion 53 are positioned in theaxial direction of the body 51 to be substantially aligned with eachother (i.e., both are positioned on the posterior end portion of thebody 51). Therefore, the large diameter portion 53 is notcircumferentially continuously provided, but breaks are provided so asto correspond to the elastic gripping portions 54.

On the body 51, a pair of protector portions 55 are formed ascantilevered portions protruding anteriorly from the anterior end edgethereof. The pair of protector portions 55 are circumferentially spacedapart, and extend linearly from the body 51 so as to be flush therewith.Further, on the body 51, preferably three front stoppers 56, forexample, are formed as cantilevered portions protruding anteriorly fromthe anterior end edge thereof. The proximal end side (or posterior endside) of each of the three front stoppers 56 is flush with the body 51,while the distal end side (or anterior end side) thereof extends in anoblique direction leaning inwardly from a direction parallel orsubstantially parallel to the axis of the body 51. The three frontstoppers 56 are positioned across the center of axis of the body 51 fromthe pair of protector portions 55.

The conductive portion 57 is formed as a cantilevered portion extendinganteriorly from the anterior end edge of the body 51 and from betweenthe pair of protector portions 55. The conductive portion 57 includes along portion 58 continuous with the anterior end of the body 51, and awide portion 59 that further projects anteriorly from the anterior end(or distal end) of the long portion 58, which results in an elasticallydeformable construction.

The proximal portion of the long portion 58 is continuous and flush withthe body 51, and extends parallel or substantially parallel to the axisof the body 51. The distal portion of the long portion 58 extends in anoblique direction leaning inwardly toward the center of axis of the body51, so that an imaginary line extending therefrom passes through thecenter of axis of the body 51 or its vicinity. The width of the longportion 58 is set to be sufficiently small for the length of the longportion 58. Therefore, the long portion 58 is capable of elasticdeformation in the radial direction of the body 51, elastic deformationin a direction intersecting with the radial direction (and intersectingwith the longitudinal direction of the long portion 58), and elastictorsional deformation around the long portion 58 itself as the axis. Theanterior end edge portion of the body 51 corresponding to the areabetween the protector portions 55 is set to be posterior to the anteriorend edge portion corresponding to the other area. Thereby, the proximalportion of the long portion 58 can be secured to be large in length. Theproximal portion of the long portion 58 is circumferentially positionedto be sandwiched between the pair of protector portions 55. The anteriorends (or distal ends) of the protector portions 55 are positioned to beanterior to the anterior end (i.e., the distal-portion-connected curvedportion) of the proximal portion of the long portion 58.

The wide portion 59 is continuous and flush with the distal portion ofthe long portion 58. Therefore, the wide portion 59 extends in anoblique direction leaning inwardly toward the center of axis of the body51. The wide portion 59 preferably has a substantially rectangularshape, which can be formed by widening the long portion 58 laterally andsymmetrically so that the lateral edges are shifted outward, and onwhich a valley 59G is formed as a V-shaped cutout on the distal end edge(or anterior end edge) thereof. The valley 59G is laterallysymmetrically formed so that its width gradually increases anteriorward.The maximum width of the valley 59G is set to be considerably largerthan the outer diameter of the outer lead 42. The size and position ofthe wide portion 59, when the conductive portion 57 is not forced intoelastic deformation or is in a free state, are set so that the outerlead 42 is partially overlapped with the wide portion 59 on a projectionplane obtained when viewed along the axial direction of the body 51, asshown in FIG. 10. Attachment of Ferrule 50 to Glass Tube 40

Next, an assembling process for attaching a ferrule 50 to a glass tube40 will be explained.

During the assembling process, while a ferrule 50 and a glass tube 40are held by respective holding devices (not shown), the ferrule 50 andthe glass tube 40 are moved relatively and coaxially so as to approacheach other. Thereby, the body 51 is fitted onto the glass tube 40. Whenthe body 51 begins engagement, the curved portions 54 a formed on thedistal ends of the three elastic gripping portions 54 have elasticcontact with the outer circumference of the glass tube 40. The curvedpotions 54 a slide on the outer circumferential surface of the glasstube 40, as the assembling process proceeds.

When the tip of the outer lead 42 has passed through the body 51, thetip of the outer lead 42 has contact with the wide portion 59 of theconductive portion 57. Thereafter, as the assembling process proceeds,the outer lead 42 pushes the wide portion 59 anteriorward while theconductive portion 57 elastically deforms due to deflection of the longportion 58. During this time, the wide portion 59 is moved or displacedradially outward as well as anteriorward. Therefore, the outer lead 42transfers to a state of contacting its outer periphery with the anteriorend edge (or distal end edge) of the wide portion 59, when theassembling process is further advanced. At that time, the outerperiphery of the outer lead 42 has contact with the sloped edge of thevalley 59G provided on the anterior end edge of the wide portion 59,because the valley 59G is thus formed on the anterior end edge of thewide portion 59. Therefore, even if the outer lead 42 is arrangedeccentrically with respect to the glass tube 40 due to radialdisplacement or is directed diagonally to the axis of the glass tube 40,the wide portion 59 moves in its width direction and relatively to theouter lead 42 due to guidance by the sloped edge of the valley 59G,resulting in the outer lead 42 necessarily fitted onto the far end ofthe valley 59G and thereby held deep therein.

When both of the holding devices have reached predetermined finalpositions after further progress in the assembling process, the ferrule50 and the glass tube 40 are axially positioned in proper positions.Thereafter, the wide portion 59 is electrically conductively fixed tothe outer lead 42 by welding, and consequently the ferrule 50 isintegrated with the glass tube 40. Then, the assembling processterminates, and the discharge tube 15 is completed.

When the ferrule 50 is attached to the glass tube 40, the body 51 iscoaxially held on the glass tube 40 due to the elastic holding functionof the three elastic gripping portions 54. A gap (airspace) is securedbetween the outer circumference of the glass tube 40 and the innercircumference of the body 51, so as to extend over the substantiallyentire circumference. The front stoppers 56 are not in contact with theglass tube 40.

The discharge tube 15, thus assembled, is fixed to relay connectors 14.At the time of fixation, the discharge tube 15 held in a horizontalposition is moved toward the front surface of the chassis 13, and theend portions and the ferrules 50 of the glass tube 40 are fitted intothe container rooms 23 of the relay connectors 14 from the front side.At that time, the pairs of elastic nipping portions 32 are pushed toopen vertically due to elastic deflection, resulting in elasticallypinching the bodies 51 of the ferrules 50. Consequently, the dischargetube 15 is held by the tube connecting portions 31 at its end portions,and is thus fixed to the chassis 13 via the relay terminals 30 and theholders 20 provided as the relay terminal 30 mounting bases. Whenattached to the chassis 13, the weight of the discharge tube 15 isreceived solely by the chassis 13 via the relay connectors 14. That is,the outer leads 42 will not be under load due to the weight of thedischarge tube 15. Further, the pair of elastic nipping portions 32 canhave contact with the contact portion 52 while elastically pinching it.Thereby, the outer lead 42 is electrically conductively connected to therelay terminal 30 via the ferrule 50.

Moreover, the power boards 16 are fixed to the back side of the chassis13. At the time of fixation, the power board 16 is moved toward thechassis 13 while the circuit board 17 is kept parallel to the chassis13, so that the wall portion 27 of each relay connector 14 and the boardconnecting portion 33 arranged along the wall portion 27 penetrate thecircuit board 17 through the fitting hole 17H and are inserted into theengaging recess 63 of the on-board connector 18. The mounting directionof the on-board connectors 18 to the relay connectors 14 is directlyopposite to the above-described mounting direction of the discharge tube15 to the relay connectors 14. That is, the mounting directions areparallel or substantially parallel to each other. When the on-boardconnectors 18 have reached a proper state of being fitted onto the relayconnectors 14, the power board 16 is screwed or otherwise fixed to thechassis 13.

When the on-board connector 18 is fitted onto the relay connector 14,the connecting portion 73 of the on-board connector 18 can have elasticcontact with the plate-shaped board connecting portion 33 of the relayconnector 14. Thereby, the output terminal 70 of the on-board connector18 is electrically conductively connected to the relay terminal 30 ofthe relay connector 14. Thus, the power board 16 is connected to thedischarge tube 15 via relay connectors 14, so that power from the powerboard 16 can be supplied to the discharge tube 15.

Operational Effects of the Present Preferred Embodiment

As described above, a discharge tube 15 of the present preferredembodiment is mounted to (or is borne by) relay connectors 14 via thebodies 51 of ferrules 50 attached to the end portions of the glass tube40. Therefore, the outer leads 42 will not be under load due to theweight of the discharge tube 15. Further, the conductive portion 57solely has elastic contact with the outer lead 42. Thus, stressconcentration on the outer lead 42 can be prevented.

Moreover, the conductive portion 57 can infallibly have contact with theouter lead 42, because a valley 59G is formed on the distal end edge ofthe conductive portion 57 so that the valley 59G of the conductiveportion 57 can be connected to the outer periphery of the outer lead 42.

The conductive portion 57 includes a long portion 58 continuous with thebody 51, and a wide portion 59 continuous with the distal end of thelong portion 58. Thus, the wide portion 59 is formed so as to havecontact with the outer lead 42, and thereby a large area of the wideportion 59 along its width direction can be secured to have contact withthe outer lead 42. Consequently, the contact therebetween can beensured. On the other hand, the long portion 58 immune to contact withthe outer lead 42 is preferably small in width and thereby be prone toelastic deflection. Consequently, contact pressure applied to the outerlead 42 can be reduced, resulting in reduction of stress on the outerlead 42.

The protruding protector portions 55 are formed on the body 51 so as tobe positioned on the respective sides of the proximal portion of theconductive portion 57. Thereby, the proximal portion of the long portion58 of the conductive portion 57 can be protected from interference withforeign substances, and consequently deformation of the conductiveportion 57 caused by interference with foreign substances can beprevented.

The elastic gripping portions 54 are formed on the body 51 so as to haveelastic contact with the outer circumference of the glass tube 40.Thereby, the ferrule 50 can be prevented from rattling or radialmovement relative to the glass tube 40, even if a large dimensionaltolerance is set for the outer diameter of glass tubes 40.

Focusing on the glass tube 40 having a substantially cylindrical shape,the body 51 preferably has a cylindrical shape substantially concentricwith the glass tube 40, and the contact portion 52 is formed along thecircumferential direction. Thereby, connection to the relay connector 14can be achieved without considering the angle of the discharge tube 15about its axis.

The contact portion 52 is formed as a rib-shaped protrusion providedcontinuously along the circumferential direction. Therefore, when thedischarge tube 15 is put on a workbench or the like, the surface of thecontact portion 52 formed as a rib-shaped protrusion may get scratcheddue to contact with the workbench. When a plurality of discharge tubes15 are bundled together, the contact portion 52 may also get scratcheddue to contact with the outer circumferential surface of the body 51attached on another discharge tube 15. However, in the present preferredembodiment, the large diameter portion 53, which is formed to have anouter diameter larger than that of the contact portion 52, can preventthe contact portion 52 from being scratched.

Further, when a plurality of discharge tubes 15, each of which has alarge diameter portion 53 describe above, are bundled together, thelarge diameter portion 53 may hit the contact portion 52 attached onanother discharge tube 15 if the discharge tubes 15 are displaced alongthe axial direction from each other. However, in the present preferredembodiment, the contact portion 52 and the large diameter portion 53 areformed respectively on the anterior and posterior end portions of thebody 51, so as to be spaced along the axial direction from each other.Thereby, a large diameter portion 53 can be prevented from interferencewith a contact portion 52.

The plurality of elastic gripping portions 54, formed on the body 51 soas to be circumferentially spaced apart, can abut on the outercircumference of the glass tube 40. Thereby, a gap (i.e., an airspacehaving a thermal conductivity lower than that of metal or syntheticresin) is secured between the outer circumference of the glass tube 40and the inner circumference of the body 51, so as to extend over thesubstantially entire circumference. Consequently, heat transfer from theglass tube 40 to the body 51 side can be prevented, and therebyreduction in internal temperature of the glass tube 40 can be prevented.The suppression of temperature reduction in the glass tube 40 canprevent cohesion of mercury encapsulated in the glass tube 40. Thisenables retention of luminescent performance.

Preferred Embodiment 2

Next, preferred embodiment 2 of the present invention will be explainedwith reference to FIGS. 19 to 23. In the present preferred embodiment 2,the constructions of elastic gripping portions 54A, 54B differ fromthose of preferred embodiment 1. The other constructions are similar topreferred embodiment 1. Therefore, the same constructions are designatedby the same symbols, and explanations for the constructions, operationsand effects thereof are omitted.

In preferred embodiment 2, preferably six elastic gripping portions 54A,54B, for example, are formed on a body 51 by punching, for example.First elastic gripping portions 54A, i.e., three of the six elasticgripping portions are formed as cantilevered portions extendingposteriorly as in preferred embodiment 1, and are arranged at evenangular intervals (i.e., at intervals of 120°) along the circumferentialdirection. Second elastic gripping portions 54B, i.e., the other threeof the six elastic gripping portions are formed as cantilevered portionsextending anteriorly or reversely from the first elastic grippingportions 54A, and are arranged at even angular intervals (i.e., atintervals of 120°) along the circumferential direction. The firstelastic gripping portions 54A and the second elastic gripping portions54B are alternately arranged along the circumferential direction, sothat circumferentially adjacent first and second elastic grippingportions 54A and 54B are spaced 60° apart.

The first elastic gripping portions 54A and the second elastic grippingportions 54B are positioned in the axial direction (or in thelongitudinal direction) so as to be substantially aligned with eachother. That is, the proximal end portions (or anterior end portions) ofthe first elastic gripping portions 54A and the distal end portions (oranterior end portions) of the second elastic gripping portions 54B areaxially positioned so as to be substantially aligned with each other,while the distal end portions (or posterior end portions) of the firstelastic gripping portions 54A and the proximal end portions (orposterior end portions) of the second elastic gripping portions 54B areaxially positioned so as to be substantially aligned with each other.The distal end portions of the six elastic gripping portions 54A, 54Bcan have elastic contact with the outer circumference of the glass tube,similarly to the elastic gripping portions of preferred embodiment 1.Due to the elastic contact, the body 51 of the ferrule 50 is arrangedconcentrically with the glass tube 40 so that a cylindrical airspaceextending substantially uniformly over the entire circumference isformed between the body 51 and the outer circumference of the glass tube40. One of the three first elastic gripping portions 54A is positionedin the circumferential direction so as to correspond to the conductiveportion 57.

According to preferred embodiment 2, the ferrule 50 can be stably heldon the glass tube 40, due to the six elastic gripping portions 54A, 54Bwhich are arranged at even angular intervals along the circumferentialdirection so as to abut on the glass tube 40. Further, the elasticgripping portions 54A, 54B have contact with the glass tube 40respectively at the posterior and anterior positions spaced along theaxial direction. Thereby, the body 51 of the ferrule 50 is preventedfrom changing its orientation and consequently forming an angle with theaxis of the glass tube 40. The stable orientation of the ferrule 50 onthe glass tube 40 prevents variation in elastic pressing force appliedby the conductive portion 57 to the outer lead 42.

Preferred Embodiment 3

Next, preferred embodiment 3 of the present invention will be explainedwith reference to FIGS. 24 to 35. In preferred embodiment 3, theconstruction of a lighting device 110 differs from that of preferredembodiment 1. The other constructions are similar to preferredembodiment 1. Therefore, the same constructions are designated by thesame symbols, and explanations for the constructions, operations andeffects thereof are omitted.

Overview of Lighting Device 110

The lighting device 110 includes a lamp unit 112 and power boards 116,as shown in FIGS. 24, 25 and 35. The lamp unit 112 includes a metallicchassis 113, which preferably has a substantially horizontally-elongatedrectangular plate shape and functions as a reflector plate. Furtherincluded are a plurality of discharge tubes 115 held in a horizontalposition and vertically arranged on the front side of the chassis 113 soas to be parallel or substantially parallel to one another, and aplurality of relay connectors 114 which are vertically arranged alongthe lateral edges of the chassis 113 so as to correspond to thedischarge tubes 115. The power boards 116 are disposed on the back sideof the chassis 113 so as to supply power to the discharge tubes 115 viathe relay connectors 114.

As shown in FIGS. 29 and 30, a plurality of substantially rectangularmounting holes 113H corresponding to the ends of the discharge tubes 115are formed through the chassis 113 so as to extend from the front sideto the back side, and are vertically arranged to be level with therespective discharge tubes 115. The relay connectors 114 are mountedthrough the respective mounting holes 113H.

Relay Connector 114

As shown in FIGS. 26 to 30, each relay connector 114 includes a holder120 preferably made of synthetic resin, and a relay terminal 131 that ishoused in the holder 120 and preferably made of metal (e.g., stainlesssteel).

The holder 120 includes a box-shaped portion 121 that forms ablock-shaped configuration as a whole, and further includes a wallportion 122 that projects backward from the back surface of thebox-shaped portion 121.

A container room 123 is formed in the box-shaped portion 121, so as tohave an opening extending from the front side to the lateral side (i.e.,the lateral side on the opposite side of the lateral edge portion of thechassis 113). The front opening portion of the opening of the containerroom 123 is provided as a receiving opening 124, into which an endportion (or ferrule 136) of the discharge tube 115 is fitted from thefront side. The lateral opening portion is provided as an escape opening125 for preventing interference with the glass tube 134 when the endportion of the discharge tube 115 is held in the container room 123. Astopper 126 is formed on the escape opening 125, so as to bulge inwardfrom the opening edge and form a plate-shaped configuration. Due to thestopper 126, the escape opening 125 is narrowed so as to form asubstantially U-shaped opening. The vertical size of the substantiallyU-shaped escape opening 125 is preferably smaller than the innerdiameter of the body 137 of the ferrule 136 and be equal to or slightlylarger than the outer diameter of the glass tube 134 of the dischargetube 115. On the escape opening 125, a concave portion 127 having asemicircular shape is formed on the far end portion of the opening edge.The radius of curvature of the concave portion 127 is set to be equal toor slightly larger than the radius of curvature of the outercircumference of the glass tube 134. On the escape opening 125, a pairof upper and lower guiding portions 128 are formed on areas of theopening edge on the front side of the concave portion 127.

On the box-shaped portion 121, an extended portion 129 extendingparallel or substantially parallel to the chassis 113 is formed on thelateral surface of the box-shaped portion 121 that includes the escapeopening 125. The extended portion 129 extends so as to separate thefront surface of the chassis 113 from the escape opening 125. A pair ofupper and lower retaining protrusions 130 are formed on the outersurface (i.e., upper surface and lower surface) of the box-shapedportion 121.

The relay terminal 131 is held within the holder 120. The relay terminal131 can be formed by bending a metallic plate that is formed into apredetermined shape by punching, for example. The relay terminal 131includes a pair of vertically symmetrical elastic pressing portions 132formed of curved plates, and further includes a board connecting portion133 formed as a flat plate-shaped portion that projects to the backside. The pair of elastic pressing portions 132, which are housed in thecontainer room 123, can deflect elastically and vertically so as toincrease distance therebetween. The vertical distance between theelastic pressing portions 132 is shortest at a position corresponding tothe front side of the concave portion 127 of the stopper 126. Theminimum distance between the elastic pressing portions 132, when theelastic pressing portions 132 are not forced into elastic deflection orare in a free state, is set to be smaller than the outer diameter of thebody 137 of the ferrule 136 attached on the discharge tube 115. On theother hand, the board connecting portion 133 projects from the backsurface of the box-shaped portion 121 so as to be exposed to the outsideof the holder 120, and extends backwards along the wall portion 122.

When the relay connector 114 is mounted to the chassis 113, the wallportion 122 of the holder 120 is inserted into a mounting hole 113H fromthe front side of the chassis 113. Thereby, the outer surface of thebox-shaped portion 121 comes in contact with the opening edge of themounting hole 113H on the front surface of the chassis 113, while theretaining protrusions 130 are locked by the opening edge of the mountinghole 113H on the back surface of the chassis 113. Thus, the chassis 113is sandwiched between the outer surface of the box-shaped portion 121 onthe front side and the retaining protrusions 130 on the back side.Thereby, the holder 120 is fixed to the chassis 113 so that its movementin the mounting direction (i.e., the through direction of the mountinghole 113H) is restricted. Then, the mounting of the relay connector 114to the chassis 113 is completed. When the relay connector 114 isattached to the chassis 113, the box-shaped portion 121 as the front endportion of the holder 120 projects (or is exposed) to the front side ofthe chassis 113 while the wall portion 122 as the back end portion ofthe holder 120 projects (or is exposed) to the back side of the chassis113.

Discharge Tube 115

Referring to FIG. 31, each discharge tube 115 is formed of a coldcathode fluorescent tube that includes a generally elongated straightglass tube 134 having a circular cross section, and elongated metallic(e.g., nickel or cobalt metal) outer leads 135 which have a circularcross section and project linearly from the respective ends of the glasstube 134 and coaxially with the glass tube 134. Further included areferrules 136 attached to the respective end portions of the glass tube134. Mercury is encapsulated in the glass tube 134. Each end portion ofthe glass tube 134 is melted into a substantially hemispherical shape byheat, and thereby forms a domed portion. The outer lead 135 penetratesthe domed portion.

Each ferrule 136 preferably is a single-piece component, which can beformed by bending or hammering a metallic (e.g., stainless steel) platethat is formed into a predetermined shape by punching, for example. Asshown in FIGS. 32 to 34, the ferrule 136 includes a body 137 and aconductive portion 140. The body 137 preferably has a substantiallycylindrical shape concentric with the glass tube 134. The inner diameterof the body 137 is preferably slightly larger than the outer diameter ofthe glass tube 134.

Three pairs of elastic gripping portions 138A, 138B are formed on thebody 137 preferably by making slit-shaped cuts in portions thereof,which are arranged at even angular intervals along the circumferentialdirection.

A first elastic gripping portion 138A, i.e., one of a pair of elasticgripping portions 138A, 138B, is generally formed as a cantileveredportion extending posteriorly (specifically, in an oblique directionslightly leaning radially inwardly), which is capable of elastic andradial deflection with a supported point on its proximal end (oranterior end). A curved portion 139 is formed on the distal end portion(or posterior end portion) of the first elastic gripping portion 138A,so as to curve in an oblique direction leaning radially outwardly. Theouter surface of the curve (or inwardly facing surface) of the curvedportion 139 is provided as a contact point when abutting on the outercircumferential surface of the glass tube 134. The imaginary line thatconnects the contact points provided on the three first elastic grippingportions 138A forms a circle concentric with the body 137. The diameterof the imaginary circle, when the first elastic gripping portions 138Aare not forced into elastic deflection or are in a free state, is set tobe smaller than the outer diameter of the glass tube 134.

A second elastic gripping portion 138B, i.e., the other of the pair ofelastic gripping portions 138A, 138B, is arranged circumferentiallyadjacent to the first elastic gripping portion 138A, and is generallyformed as a cantilevered portion extending anteriorly or reversely fromthe first elastic gripping portion 138A (specifically, in an obliquedirection slightly leaning radially inwardly), which is capable ofelastic and radial deflection with a supported point on its proximal end(or posterior end). The distal end of the second elastic grippingportion 138B is provided as a contact point when abutting on the outercircumferential surface of the glass tube 134. The imaginary line thatconnects the contact points provided on the three second elasticgripping portions 138B forms a circle concentric with the body 137. Thediameter of the imaginary circle, when the second elastic grippingportions 138B are not forced into elastic deflection or are in a freestate, is preferably smaller than the outer diameter of the glass tube134.

On the body 137, a pair of protector portions are formed as cantileveredportions protruding anteriorly from the anterior end edge thereof. Thepair of protector portions are arranged circumferentially spaced apart,and extend linearly from the body 137 so as to be flush therewith. Theconductive portion 140 is provided as a cantilevered portion thatextends anteriorly from between the pair of protector portions. Theconductive portion 140 includes a long portion 141 continuous with theanterior end of the body 137, and a cylindrical portion 142 that furtherprojects anteriorly from the anterior end (or distal end) of the longportion 141.

The long portion 141 includes a proximal portion 141 a that extends fromthe body 137 so as to be flush with the body 137 and parallel orsubstantially parallel to the axis thereof, and further includes anintermediate portion 141 b that extends radially inwardly from thedistal end of the proximal portion 141 a toward the axis of the body137. Further included is a distal portion 141 c that extends from thedistal end of the intermediate portion 141 b and parallel orsubstantially parallel to the axis of the body 137. The cylindricalportion 142 is connected to the distal end of the distal portion 141 c.The width of the long portion 141 is set to be sufficiently small forthe length of the long portion 141. Therefore, the long portion 141 iscapable of elastic deformation in the radial direction of the body 137,elastic deformation in a direction intersecting with the radialdirection (and intersecting with the longitudinal direction of the longportion 141), and elastic torsional deformation around the long portion141 itself as the axis.

The cylindrical portion 142, which can be formed by bending a portionlaterally extending from the distal end of the long portion 141 into acylindrical shape, is arranged substantially coaxially with the body137. The cylindrical portion 142 is capable of displacement around theaxis of the ferrule 136 and radial displacement, due to elasticdeflection of the long portion 141. Attachment of Ferrule 136 to GlassTube 134

Next, an assembling process for attaching a ferrule 136 to a glass tube134 will be explained.

During the assembling process, while a ferrule 136 and a glass tube 134are held by respective holding devices (not shown), the ferrule 136 andthe glass tube 134 are moved relatively and coaxially so as to approacheach other. Thereby, the body 137 is fitted onto the glass tube 134.When the body 137 begins engagement, the contact points provided on thedistal end portions of the three pairs of elastic gripping portions138A, 138B have elastic contact with the outer circumference of theglass tube 134. The contact points slide on the outer circumferentialsurface of the glass tube 134, as the assembling process proceeds. Then,the tip of the outer lead 135 having passed through the body 137 beginsto enter the hollow of the cylindrical portion 142. When both of theholding devices have thereafter reached predetermined final positions,the ferrule 136 and the glass tube 134 are axially positioned in properpositions, resulting in the tip end portion of the outer lead 135circumferentially surrounded by the cylindrical portion 142. At thattime, the tip end portion of the outer lead 135 will not greatlyprotrude from the anterior end of the cylindrical portion 142. That is,it slightly protrudes out of the cylindrical portion 142, or is alignedwith the anterior end of the cylindrical portion 142, or alternativelyit is located within the cylindrical portion 142.

Thereafter, the cylindrical portion 142 is clamped so as to deform withdiameter reduction. After being clamped, the cylindrical portion 142 iselectrically conductively fixed to the outer lead 135 by welding, andconsequently the ferrule 136 is integrated with the glass tube 134.Then, the assembling process terminates, and the discharge tube 115 iscompleted.

When the ferrule 136 is attached to the glass tube 134, the body 137 isconcentrically held on the glass tube 134 due to the elastic holdingfunction of the three pairs of elastic gripping portions 138A, 138B. Agap (airspace) is secured between the outer circumference of the glasstube 134 and the inner circumference of the body 137, so as to extendover the substantially entire circumference.

Instead of the cylindrical portion 142, a U-shaped connecting portion142 a may be provided as shown in FIGS. 43 and 44. In this case, after aglass tube 134 is fitted into a ferrule 136, the U-shaped connectingportion 142 a is bended so as to hug the outer lead 135, in order toachieve electrical connection between the outer lead 135 and theconnecting portion 142 a. According to the present preferred embodimentthus including the bendable U-shaped connecting portion 142 a,electrical connectivity with the outer lead 135 can be further improved.

Mounting of Discharge Tube 115 to Relay Connectors 114

The discharge tube 115, thus assembled, is fixed to relay connectors114. At the time of fixation, the discharge tube 115 held in ahorizontal position is moved toward the front surface of the chassis113, and the end portions and the ferrules 136 of the glass tube 134 arefitted into the container rooms 123 of the relay connectors 114 from thefront side. At that time, the pair of elastic pressing portions 132 arepushed by the body 137 of the ferrule 136 so as to open vertically dueto elastic deflection. After the body 137 has passed through theshortest-distance portions of the elastic pressing portions 132, thebody 137 is pulled deep into the container room 123 due to elasticrestoring forces of the elastic pressing portions 132, resulting in thebody 137 abutting on the bottom of the container room 123. Then, themounting of the discharge tube 115 is completed.

The discharge tube 115 thus mounted is held by the pairs of elasticpressing portions 132 at its end portions, and thereby is fixed to thechassis 113 via the relay terminals 131 and the holders 120 provided asthe relay terminal 131 mounting bases. At that time, the weight of thedischarge tube 115 is received solely by the chassis 113 via the relayconnectors 114. That is, the outer leads 135 will not be under load dueto the weight of the discharge tube 115.

The pair of elastic pressing portions 132 can have elastic contact withthe outer circumferential surface of the body 137, and thereby the outerlead 135 is electrically conductively connected to the relay terminal131 via the ferrule 136. Further, the glass tube 134 is held due toelastic restoring forces of the pair of elastic pressing portions 132,so as to be pressed against the concave portion 127 of the stopper 126.Therefore, when viewed along the axial direction of the discharge tube115, the body 137 appears to be positioned so as to partially overlapwith the stopper 126. That is, the end edge of the body 137 on theopposite side of the conductive portion 140 is axially positioned inproximity to the stopper 126 so as to be partially faced therewith.

The extended portion 129 is formed on the outer surface of the holder120, which is perpendicular to the surface of the chassis 113 andincludes the escape opening 125 of the container room 123, so as toprotrude from between the chassis 113 and the escape opening 125 andextend along the surface of the chassis 113. This results in a longcreepage distance from the inside of the container room 123 to the frontsurface of the chassis 113. Thereby, a leak, from the discharge tube 115held in the container room 123 to the chassis 113 outside the holder120, can be prevented.

Overview of Power Board 116

Each power board 116 includes a circuit board 117 having a circuitformed on its back surface (i.e., the surface on the opposite side ofthe chassis 113), electronic components 119 mounted on the back surfaceof the circuit board 117, and a plurality of on-board connectors 118mounted on the back surface of the circuit board 117.

The circuit board 117 preferably has a vertically-elongated rectangularshape as a whole, and is formed using a phenolic paper-base copper-cladlaminated board (known as a phenolic paper). A plurality of fittingholes 117H having a vertically-elongated rectangular shape are formedthrough the circuit board 117 so as to extend from the front side to theback side. The plurality of fitting holes 117H are arranged verticallyalong the lateral side edge of the circuit board 117 so as to correspondto the above-described relay terminals 131 (or relay connectors 114).Each on-board connector 118 includes a housing made of synthetic resin,and an output terminal (not shown) that is completely contained in thehousing and made of metal (e.g., nickel silver). The on-board connectors118 are arranged along the lateral side edge of the circuit board 117 soas to correspond to the respective fitting holes 117H. A fitting space(not shown) is provided on the outer surface of the housing so as tocorrespond to the fitting hole 117H, and the output terminal is partlyexposed to the fitting space.

While the circuit board 117 is kept parallel or substantially parallelto the chassis 113, the power board 116 is moved toward the chassis 113from the back side and is fixed thereto. At the time of fixation, thewall portions 122 of the relay connectors 114 and the board connectingportions 133 arranged along the wall portions 122 penetrate the circuitboard 117 through the fitting holes 117H and are inserted into thefitting spaces of the on-board connectors 118. Thereby, the on-boardconnectors 118 are fitted onto the relay connectors 114, and the outputterminals are conductively connected to the relay terminals 131.

Operational Effects of Preferred Embodiment 3

In preferred embodiment 3, when a discharge tube 115 is supported onrelay connectors 114, the stoppers 126 lock the ferrules 136. Therefore,the discharge tube 115 is secure from axial movement relative to therelay connectors 114. That is, if a force is applied to the dischargetube 115 so as to cause movement to the right, the stopper 126 catchesthe left-adjacent ferrule 136 attached on the left end portion of thedischarge tube 115 so that the movement of the discharge tube 115 to theright is restricted. If a force is applied to the discharge tube 115 soas to cause movement to the left, the stopper 126 catches theright-adjacent ferrule 136 attached on the right end portion of thedischarge tube 115 so that the movement of the discharge tube 115 to theleft is restricted. Thus, the axial movement of the discharge tube 115to either right or left is restricted, and therefore the tip of theouter lead 135 is prevented from hitting the wall of the container room123 on the opposite side of the escape opening 125.

The stopper 126 can engage with and lock the end edge of the ferrule136, and therefore a hole that can engage with the stopper 126 is notrequired to be formed on the outer circumference of the ferrule 136. Asa result, processing cost can be reduced, and reduction in strength ofthe ferrule 136 can be prevented.

In the case of a construction in which a stopper 126 can engage with theend edge of a ferrule 136 on the side of the conductive portion 140, theconductive portion 140 extending from the end edge of the ferrule 136may preclude the end edge of the ferrule 136 from engaging with thestopper 126, when the ferrule 136 is attached at some angle about itsaxis. However, in preferred embodiment 3, the stopper 126 is arranged toengage with the end edge on the opposite side of the conductive portion140. Therefore, the conductive portion 140 will not preclude the ferrule136 from engaging with the stopper 126, and consequently the ferrule 136can infallibly engage with the stopper 126.

The conductive portion 140 includes a cylindrical portion 142, which canbe circumferentially connected to the outer lead 135 so as to surroundit. Thereby, the conductive portion 140 can be prevented fromdisengaging from the outer lead 135. That is, the cylindrical portion142 will not disengage from the outer lead 135 when the cylindricalportion 142 is clamped. Therefore, the conductive portion 140 can beinfallibly connected to the outer lead 135.

The margin for engagement of a ferrule 136 with a stopper 126corresponds to half of the dimensional difference between the outerdiameters of the glass tube 134 and the ferrule 136. In preferredembodiment 3, ferrules 136 are concentrically held on a glass tube 134due to the elastic gripping portions 138A, 138B. Therefore, if theferrule 136 is set to be large, a large dimensional difference can besecured between the inner diameter thereof and the outer diameter of theglass tube 134. Thereby, the margin for engagement of the ferrule 136with the stopper 126 can be increased, resulting in reliable restrictionof movement of the discharge tube 115.

The concave portion 127 is formed on a stopper 126, so as to abut on theouter circumference of a glass tube 134 when the ferrule 136 engageswith the stopper 126. Further, the pair of elastic pressing portions 132capable of pressing the discharge tube 115 toward the concave portion127 side are provided in the relay connector 114. Specifically, the pairof elastic pressing portions 132 press the discharge tube 115 toward theconcave portion 127 side, obliquely from above and obliquely from below,i.e., vertically symmetrically. Thereby, the glass tube 134 is preventedfrom disengaging from the concave portion 127, and therefore theengagement of the ferrule 136 with the stopper 126 can be reliablymaintained.

The relay connector 114 is formed by mounting a relay terminal 131 in aholder 120 made of synthetic resin. In preferred embodiment 3, thestopper 126 is formed on the synthetic-resin holder 120. That is, astopper is not required to be formed on the relay terminal 131, andtherefore the material for manufacturing the relay terminals 131 can bereduced. Considering that the material cost for synthetic resin isgenerally lower than that for metal, the material cost for relayconnectors 114 can be reduced according to preferred embodiment 3.

Preferred Embodiment 4

Next, preferred embodiment 4 of the present invention will be explainedwith reference to FIGS. 36 to 42. In preferred embodiment 4, theconstructions of devices for supporting a discharge tube 115 differ fromthose of preferred embodiment 3. The other constructions are similar topreferred embodiment 3. Therefore, the same constructions are designatedby the same symbols, and explanations for the constructions, operationsand effects thereof are omitted.

Overview of Grounding Member 150

In preferred embodiment 3, the end portions of a discharge tube 115 aresupported by relay connectors 114, each of which includes a holder 120and a relay terminal 131. In preferred embodiment 4, as shown in FIGS.36 to 38, one of the end portions of a discharge tube 115 is supportedby the same relay connector 114 as preferred embodiment 3, while theother end portion of the discharge tube 115 is supported by a groundingmember 150.

As shown in FIG. 39, the grounding member 150 includes an elongatedsupport plate 151 fixed to the chassis 113 so as to be along one of thelateral edge portions thereof, and further includes a plurality ofgrounding terminals 152 conductively mounted on the front surface of thesupport plate 151. As shown in FIG. 41, mounting holes 151H are formedthrough the support plate 151 so as to correspond three-to-one with thegrounding terminals 152. The support plate 151 is formed of a substrateor a metallic plate.

On the other hand, as shown in FIG. 40, each grounding terminal 152,which can be formed by bending a metallic (e.g., nickel silver) platethat is formed into a predetermined shape by punching, includes a baseportion 153 and a pair of elastic pressing portions 154 which extendvertically symmetrically from the respective upper and lower edgeportions of the base portion 153 to the front side. Further included isa stopper 155 that extends from one of the lateral edge portions of thebase portion 153 to the front side.

The pair of elastic pressing portions 154 are provided on the lateraledge portion on the opposite side of the stopper 155, so as to formbulging curves toward each other. The elastic pressing portions 154 arecapable of elastic deflection so as to increase the distancetherebetween. The minimum distance between the pair of elastic pressingportions 154, when the elastic pressing portions 154 are free fromelastic deflection, is preferably smaller than the outer diameter of theglass tube 134 of a discharge tube 115.

The stopper 155 is raised from the base portion 153, so as to form aright angle with the axis of the discharge tube 115. A concave portion156 is formed on the stopper 155, so as to sag in a substantiallycircular arc. On a relay connector 114 of preferred embodiment 3, a pairof guiding portions 128 are raised from the respective upper and lowersides of the concave portion 127 of the stopper 126. However, inpreferred embodiment 4, the heights of portions raised from therespective upper and lower sides of the concave portion 156 of the baseportion 153 are reduced to be short. That is, elements corresponding tothe guiding portions 128 of preferred embodiment 3 are not provided.Therefore, the metallic material required for grounding terminals 152can be reduced, compared to including guiding portions.

Three leg portions 157 are further formed on the base portion 153, so asto be integrated therewith. Two of the three leg portions 157 areprovided between the elastic pressing portions 154 and the stopper 155,so as to project from the respective upper and lower edge portions ofthe base portion 153 to the opposite side of the elastic pressingportions 154 or the stopper 155 (i.e., to the back side). The remainingone of the leg portions 157 is provided on the lateral edge of the baseportion 153 on the opposite side of the stopper 155, so as to projectfrom the intermediate position between the elastic pressing portions 154to the opposite side of the elastic pressing portions 154 or the stopper155 (i.e., to the back side).

The grounding terminal 152 is not housed in a member such as a plastichousing, i.e., barely provided, and is conductively fixed to the supportplate 151 by soldering or the like so that its leg portions 157penetrate through the mounting holes 151H (See FIG. 42). Thus, theplurality of grounding terminals 152 are mounted to the common supportplate 151, and thereby are conductively connected to one another via thesupport plate 151. Power boards are not connected to the groundingmembers 150, and the support plate 151 is conductively connected to thechassis.

Mounting of Discharge Tube 115 to Grounding Terminal 152

When a discharge tube 115 is fixed to a grounding terminal 152, thedischarge tube 115 held in a horizontal position is moved toward thefront surface of the chassis 113, and the end portion and the ferrule136 of the glass tube 134 are fitted between the pair of upper and lowerelastic pressing portions 154 from the front side. At that time, thepair of elastic pressing portions 154 are pushed by the body 137 of theferrule 136 so as to open vertically due to elastic deflection. Afterthe body 137 has passed through the shortest-distance portions of thepair of elastic pressing portions 154, the body 137 is pulled toward thebase portion 153 side due to elastic restoring forces of the elasticpressing portions 154, resulting in the body 137 abutting on the baseportion 153. Then, the fixation of the discharge tube 115 is completed.The other end portion of the discharge tube 115 is fixed to a relayconnector 114 in a similar manner to preferred embodiment 3.

The discharge tube 115 thus mounted is supported by the relay connector114 and the grounding member 150 at its respective end portions. Thepairs of elastic pressing portions 132, 154 can have elastic contactwith the outer circumferential surfaces of the bodies 137 of theferrules 136, and thereby the outer leads 135 are electricallyconductively connected to the relay terminal 131 and the groundingterminal 152 via the ferrules 136. Further, the glass tube 134 is helddue to elastic restoring forces of the pairs of elastic pressingportions 132, 154, so as to be pressed against the concave portions 127,156 of the stoppers 126, 155. Therefore, when viewed along the axialdirection of the discharge tube 115, the body 137 appears to bepositioned so as to partially overlap with the stopper 126 or 155. Thatis, the end edge of the body 137 on the opposite side of the conductiveportion 140 is axially positioned in proximity to the stopper 126 or 155so as to be partially faced therewith.

As shown in FIGS. 45 and 46, protector portions 551 may be provided onthe grounding terminal 152. Each protector portion 551 includes arestricting portion 552 for an elastic pressing portion, and furtherincludes an abutting portion 553 for abutting on the support plate. Whenthe grounding terminal 152 is mounted and fixed to the support plate151, the abutting portions 553 abut on or are located close to thesupport plate 151. If some kind of external force is applied to theelastic pressing portions 154 so that they are pushed to open, theyfirst become in contact with the restricting portions 552 during thecourse of opening. The abutting portions 553 serve as supports forpreventing the protector portions 551 from collapsing, when anadditional load is thereafter applied. The protector portions 551 areconnected to the feet of the elastic pressing portions 154, andtherefore the abutting portions 553 should be formed lateral to theconnection portion in order that the abutting portions 553 work. Notethat abutting portions 553 located at a longer distance from theconnection portion are more effective.

Operational Effects of Preferred Embodiment 4

In preferred embodiment 4, when a discharge tube 115 is supported on arelay connector 114 and a grounding member 150, the stopper 126 of theholder 120 and the stopper 155 of the grounding terminal 152 lock theferrules 136 attached on the respective ends of the discharge tube 115.Therefore, the discharge tube 115 is secure from axial movement relativeto the relay connector 114.

That is, if a force is applied to the discharge tube 115 so as to causemovement from the relay connector 114 side to the grounding member 150side, the ferrule 136 attached on the end portion of the discharge tube115 on the relay connector 114 side is caught by the stopper 126 of theholder 120 so that the movement of the discharge tube 115 to thegrounding member 150 side is restricted. If a force is applied to thedischarge tube 115 so as to cause movement from the grounding member 150side to the relay connector 114 side, the ferrule 136 attached on theend portion of the discharge tube 115 on the grounding member 150 sideis caught by the stopper 155 of the grounding terminal 152 so that themovement of the discharge tube 115 to the relay connector 114 side isrestricted. Thus, the axial movement of the discharge tube 115 to eitherright or left is restricted, and therefore the tip of the outer lead 135is prevented from hitting the wall of the container room 123 on theopposite side of the escape opening 125 or hitting the sidewall of thechassis 113.

The concave portion 156 is formed on the stopper 155 of a groundingterminal 152, so as to abut on the outer circumference of a glass tube134 when the ferrule 136 is engaged with the stopper 155. Further, thepair of elastic pressing portions 154 capable of pressing the dischargetube 115 toward the concave portion 156 side are provided on thegrounding terminal 152. Specifically, the pair of elastic pressingportions 154 press the discharge tube 115 toward the concave portion 156side, obliquely from above and obliquely from below, i.e., verticallysymmetrically. Thereby, the glass tube 134 is prevented from disengagingfrom the concave portion 156, and therefore the engagement of theferrule 136 with the stopper 155 can be reliably maintained.

On the grounding member 150, the stoppers 155 are integrated with therespective grounding terminals 152 to provide a conductive connection tothe ferrules 136. Thereby, the number of components can be reduced inpreferred embodiment 4, compared to including stoppers provided asseparate members from the grounding terminals.

Other Preferred Embodiments

The present invention is not limited to the preferred embodimentsexplained in the above description made with reference to the drawings.The following preferred embodiments may be included in the technicalscope of the present invention, for example.

The discharge tube is not limited to a cold cathode fluorescent tube. Ahot cathode fluorescent tube, a xenon tube or the like may be usedinstead.

The material for a ferrule is not limited to metal. A conductive resinor a conductive rubber may be used instead.

The outer leads, linearly projecting from a glass tube, are not limitedto being arranged concentrically with the glass tube, but rather may bearranged radially eccentrically with respect to the axis of the glasstube.

The outer leads, linearly projecting from a glass tube, are not limitedto being arranged parallel or substantially parallel to the axis of theglass tube, but rather may be arranged at an angle with the axis of theglass tube.

The outer leads are not limited to being formed linearly, but rather maybe formed crookedly.

The conductive portion may be connected anteriorly to the tip of theouter lead, instead of being connected to the outer periphery of theouter lead.

A curved portion may be formed on the distal end portion of theconductive portion, so that the outer surface of the curve of the curvedportion can be connected to the outer periphery of the outer lead,instead of connecting the distal end edge of the conductive portion tothe outer periphery of the outer lead.

The valley formed on the distal end edge of a conductive portion may beeliminated, so that the straight distal end edge can be connected to theouter periphery of the outer lead.

The valley formed on the distal end edge of a conductive portion is notlimited to being V-shaped, but rather may be U-shaped,rectangular-shaped or semicircular-shaped.

The conductive portion may have a constant width along its entirelength.

The protector portions may be eliminated from a ferrule.

Instead of one conductive portion, a plurality of conductive portionsmay be provided. In this case, the plurality of conductive portions maybe arranged at intervals along the circumferential direction, oralternatively, may be displaced along the axial direction (i.e., thedirection parallel to the projecting direction of the outer lead) fromone another.

The body of a ferrule is not limited to having a cylindrical shape, butrather may be ring-shaped or substantially C-shaped.

The contact portion of a ferrule is not limited to being formed of acircumferentially continuous rib, but rather may be formed of aplurality of protrusions which are arranged at intervals along thecircumferential direction.

The contact portion of a ferrule is not limited to being formed of arib-shaped protrusion. The outer circumferential surface of the body maybe partially used as a contact portion without modification.Alternatively, an elastic portion, to be used as a contact portion, maybe formed by making a cut in the body and lifting up that portion.

The number of elastic gripping portions is not limited to three or six,but rather may be two or less, or four, five, seven or more.

The elastic gripping portions are not limited to being formed ofcantilevered portions extending anteriorly or posteriorly, but rathermay be formed of two-point supported portions which are supported on thebody at their anterior and posterior ends.

The plurality of elastic gripping portions may be arranged atunequally-spaced intervals, instead of being arranged at equally-spacedintervals along the circumferential direction.

In order to secure circumferential airspace between the outercircumference of a glass tube and the inner circumference of the body ofa ferrule, one or a plurality of elastic gripping portions and one or aplurality of inelastic receiving portions (e.g., inwardly bulgingportions formed by hammering the body in part) may be formed so as toabut on the outer circumference of the glass tube, instead of aplurality of elastic gripping portions capable of elastic contact withthe outer circumference of the glass tube.

The large diameter portion may be eliminated from the body of a ferrule.

The contact portion and the large diameter portion of a ferrule may bearranged in proximity to each other, instead of being arranged spacedapart on the respective axial end portions of the body.

On the body, the axial positions may be switched between the anteriorcontact portion and the posterior large diameter portion.

The size and position of the wide portion, when the conductive portionis not forced into elastic deformation or is in a free state, may be setso that the axis (as an imaginary line) of the body penetrates the wideportion out of the cutout area corresponding to the valley. In thiscase, on a projection plane obtained when viewed along the axialdirection of the body, the outer lead can partially or completelyoverlap with the wide portion.

The conductive portion may be indirectly connected to the outer lead bysoldering or welding, instead of being directly connected to the outerlead. In this case, the elastic pressing force of the conductive portionapplied to the outer lead can be eliminated.

In preferred embodiment 2, the elastic gripping portions are preferablyarranged so as to abut on the outer circumference of the glass tube attwo positions spaced along the axial direction of the body. However,elastic gripping portions may be provided so as to abut on the glasstube at axially-spaced three or more positions.

In preferred embodiment 2, two types of elastic gripping portions, whichextend in reverse directions from each other, are preferably arranged soas to abut on the glass tube at axially-spaced two positions. However,alternatively, two types (or plural types) of elastic gripping portions,which extend in the same direction and are axially displaced from eachother, may be provided.

The output terminal may be formed into a predetermined shape simply bypunching a metallic material, without bending, for example.

The display panel of the display device is not limited to having TFTs asswitching elements, but rather may include, as switching elements,elements other than TFTs such as MIM (Metal Insulator Metal) elements.

The display device is not limited to a liquid crystal display device.Various display devices requiring a lighting device on the back side ofa display panel can be included.

The power source is not limited to a power board that includeselectronic components mounted on a circuit board, but rather may beprovided by connecting electronic components by wires without using acircuit board.

The device for bearing the body of a ferrule is not limited to a relayconnector. The ferrule may be directly (i.e., without using a relayconnector) fixed to a connector (e.g., an inverter connector) directlymounted on the power board. Alternatively, a dedicated bearing device,to which the ferrule is fixed, may be provided separately from the powersupply path formed between the power source and the outer lead.

The on-board connectors may be eliminated from a circuit board, so thatthe relay connectors are connected to the power source (or power board)via cables.

In the above preferred embodiments, the conductive portion is preferablyfixed to the outer lead by welding, for example. However, in the case ofa conductive portion capable of elastic (or abutting) contact with theouter lead, the connection can be secured solely by the elastic force ofthe conductive portion without fixation such as welding.

The conductive connection between the cylindrical portion of theconductive portion and the outer lead may be achieved by soldering.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing the scope andspirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

1. A discharge tube capable of receiving power supply from a power source and capable of being borne by a bearing device, said discharge tube comprising: a glass tube; an outer lead arranged to project from an end portion of said glass tube and be capable of receiving power supply from said power source; and a ferrule having a body mounted to an outer circumference of said glass tube, a conductive part electrically connected to said body and said outer lead, and an elastic part having deformable construction located between said body and said conductive part, said body being capable of being borne by said bearing device and capable of being electrically connected to said power source.
 2. A discharge tube as in claim 1, wherein said elastic part is deformable so as to allow said conductive part to move in an axial direction of said outer lead.
 3. A discharge tube as in claim 1, wherein said elastic part is capable of elastic torsional deformation.
 4. A discharge tube as in claim 1, wherein said conductive part has a cylindrical portion surrounding at least a part of said outer lead.
 5. A discharge tube as in claim 1, wherein said conductive part is crimped to said outer lead, so as to surround at least a part of said outer lead.
 6. A discharge tube as in claim 1, wherein said conductive part is welded to said outer lead, so as to surround at least a part of said outer lead.
 7. A discharge tube as in claim 1, wherein said conductive part is crimped and welded said outer lead, so as to surround at least a part of said outer lead.
 8. A lighting device for a display device, comprising: a power source; a discharge tube as in claim 1; and a chassis provided as a mounting base for said power source and said discharge tube.
 9. A display device comprising: a lighting device for a display device that includes: a power source; a discharge tube as in claim 1; and a chassis provided as a mounting base for said power source and said discharge tube; and a display panel arranged on a front side of said lighting device.
 10. A television receiver comprising: a lighting device for a display device that includes: a power source; a discharge tube as in claim 1; and a chassis provided as a mounting base for said power source and said discharge tube; and a display panel arranged on a front side of said lighting device. 